Re: [Qemu-devel] [PATCH for-2.5] configure: Don't disable optimization for non-fortify builds

[Paolo Bonzini <pbonzini@redhat.com>]

On 09/11/2015 16:31, Peter Maydell wrote:
> On 9 November 2015 at 15:28, Paolo Bonzini <pbonzini@redhat.com> wrote:
>>
>>
>> On 09/11/2015 16:14, Peter Maydell wrote:
>>> Commit b553a0428014636bc inadvertently disabled optimization
>>> for all non-fortify builds. Fix this bug so we only do an
>>> unoptimized build if we want debug.
>>>
>>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>>> ---
>>>  configure | 2 ++
>>>  1 file changed, 2 insertions(+)
>>>
>>> diff --git a/configure b/configure
>>> index b687764..46fd8bd 100755
>>> --- a/configure
>>> +++ b/configure
>>> @@ -4451,6 +4451,8 @@ if test "$gcov" = "yes" ; then
>>>    LDFLAGS="-fprofile-arcs -ftest-coverage $LDFLAGS"
>>>  elif test "$fortify_source" = "yes" ; then
>>>    CFLAGS="-O2 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 $CFLAGS"
>>> +elif test "$debug" = "no"; then
>>> +  CFLAGS="-O2 $CFLAGS"
>>>  fi
>>
>> I think what was intended is:
>>
>> if test "$gcov" = "yes" ; then
>>   CFLAGS="-fprofile-arcs -ftest-coverage -g $CFLAGS"
>>   LDFLAGS="-fprofile-arcs -ftest-coverage $LDFLAGS"
>> elif test "$debug" = "no" ; then
>>   if test "$fortify_source" = "yes"; then
>>     CFLAGS="-U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 $CFLAGS"
>>   fi
>>   CFLAGS="-O2 $CFLAGS"
>> fi
>>
>> ... so that --enable-debug does not disable _FORTIFY_SOURCE.
> 
> Commit b553a04280146 specifically sets fortify_source=no
> in the handling of the --enable-debug option, so John
> obviously intended that it should disable _FORTIFY_SOURCE.
> The feature_test_macros(7) manpage says _FORTIFY_SOURCE
> only kicks in at -O1 and above anyway, so that makes sense.

You're right.  The two are the same then, preference is of course
subjective.  Feel free to commit yours!


Paolo